X11 -> Cut & Paste qeuestion

Hello
Work with Windows7 and Xming as XServer installed, here i have connection over
SSH to Netbsd from this i use the Application "Xournal, to-do any notes" and
this "Xournal" appear on my windows machine. the created snapshot wasn't paste
in Application "Xournal" !. For me it's easier and faster to explain as exclude
all comment, but this "Paste from Picture" doesn't work.
I can technically understand that this are not easy way, but here exist a
possibility to fruition?
Thanks and best regards for any help or feedback
Mauri